Armo61, et al,
For the pilot house front bulkhead, I used styrene sheet that is slightly thinner than the other 3 walls provided by Lindberg. These vessels are "tin cans" so I was trying to depict scale thickness (more or less) in that area, especially where one can see the thickness of that wall through the portholes.
If you wanted to keep the twin rudder setup, and the plastic kit parts can be brittle, why not try fabricating new ones like
raaartygunner mentioned? I have used brass sheet, rod and tubing to make rudders along with a tiller arm just for such a conversion. I used 1/8" brass rod, slotted with a Dremel cut-off wheel and a suitable brass rudder soldered into the slot and this rides in a rudder tube whose inside diameter matches the rudder post's outside diameter; a "telescoping" fit. Used grease to seal it up a bit but made sure the end of the rudder tube inside the hull was above the waterline.
Aside from that, almost every person who has made the RC conversion of this destroyer complains that it is too topheavy, dangerously unstable, that it rolls in turns or heavy "seas" and can ship water over the bow, etc. The real Fletchers performed the same way and the latest complaint here is that with a single rudder the turns will be too wide or not as agile. Well guess what, the real Fletchers purportedly had the same problem and I have heard that the Iowa class battleships could outhandle much smaller naval vessels of the era.
I think an Iowa class may have turned inside of a destroyer, possibly a Fletcher, to the amazement of everyone...
I think scale authenticity is a neat thing. Anyway, the single rudder of the Fletcher class has a fairly large area and it is almost what I would call a balanced rudder; one that is affixed more or less to the centerline of the rudder shaft. When turned, a large portion of the rudder is in contact with the propwash of whichever prop is on the inside of the turn, so at least the thrust of the engine is working on part of the rudder. Here's pic:
http://www.worldaffairsboard.com/attachments/naval-warfare/23102d1291926005-destroyers-fletcher-class-screws_dsc00558.jpg